Twine bricked after update?

I very recently bought two twines, I started the setup of the first today. It promted me to do a software-update, which i did, but afterwards it seems not to work (I am not quite sure if this happend during the update or a short time afterwards. Now I have no connection with the twine, it has no lights, and it seems to be completly dead, new batteries or plugging in USB makes no difference. Any tips? I didn't get any error messages during the update.